Drying attachment for spray gun



April 18, 1961 R. c. CHILTON DRYING ATTACHMENT FOR SPRAY GUN Filed Sept. 16, 1957 FlG.2.

FIGJ.

FIG.4.

INVENTOR.

RO ERT C. CHILTON ATTORNEYS ilnited States Patent DRYING ATTACHMENT FOR SPRAY GUN Robert C. Chilton, 1409 Grayton Road, Grosse Pointe Park 30, Mich.

Filed Sept. 16, 1957, Ser. No. 684,130

g -12 Claims. (Cl. 219-39) The present invention relates to an improved attachment for spray guns to promote and expedite the drying of paints, latex solutions and other liquid compounds sprayed, by heating the compound as it issues from a nozzle of a conventional type gun. More particularly, the invention deals with an attachment for this purpose which avoids direct heating of the nozzle, and in which an atomized jet of paint, rubber latex or other coating compound is heated by hot-air stream or blast converging in a zone substantially forwardly of the nozzle, without direct heating of the latter.

It has previously been proposed to assist in and expedite the drying of coating compounds applied by a conventional spray gun by applying 'to the nozzle or head of the gun, at which the liquid coating is subjected to injector action of opposed air jets, appropriate heating provisions, such as an annular electrical heating unit. However, this type drier is undesirable, particularly when readily coagulative compounds such as rubber latex are sprayed, because the excessive heating of the nozzle causes coagulating of the coating in the nozzle interior.

It is therefore a general object of the invention to provide an attachment for a conventional spray gun which acts to heat and thus assist drying of the issuing spray without heat transfer to the nozzle. The result is that coagulation in the gun head or nozzle, such as occurs in the use of nozzle heating devices, particularly in non-spraying intervals, is prevented, and loss of time in cleaning or purging is avoided.

Another object of the invention is to provide an attachment in which heated air is applied to the issuing airliquid spray substantially forwardly of the nozzle, to insure against undesired heating of the latter. In furtherance of this object an air heating and jetting housing is mounted in a position forwardly and out of heat transfer relation to the nozzle.

A still further object is to provide an attachment for the above purpose, in the form of a device readily and quickly applicable to and detachable from the spray gun structure. More particularly, the device comp rises an annular housing adapted to be mounted coaxially of the gun nozzle and needle valve, together with provisions to supply compressed air to an internal annular chamber of the housing for heating therein, and to issue the air in a series of forwardly convergent jets, preferably arranged in two arcuate series, one at either side of the spray.

A further object is to provide an attachment as described, in which an internal electrical heating unit of annular outline is disposed in the housing to heat the air jets referred to.

A still further object is to provide an attachmentor unit of this sort, in which the hot air jet orifices are disposed in a relation to the spray orifices of the gun nozzle such as to maintain the desired spray outline, for example, horizontally or vertically fanned, etc.

.The foregoing as well as other objects will become more apparent as this description proceeds, especially when considered in connection with the accompanying drawings illustrating a preferred embodiment of the invention wherein:

Fig. 1 is a side elevational view of a conventional type spray gun equipped with the improved drying attachment of the invention;

Fig. 2 is a fragmentary view partially broken away and in horizontal section along the line 22 of Fig. 1;

Fig. 3 is an enlarged scale front elevational view of the drying attachment, with nozzle provisions of the gun schematically indicated; and

Fig. 4 is a view in horizontal section along a line corresponding to the line 4-4 of Fig. 3.

The reference numeral 10 generally designates a conventional type of paint spray gun, widely available on the market and in practically universal use. It includes a forward mixing nozzle 11, a hand grip 12, a valve control trigger 13, and a slidable needle valve 14 controlled by the trigger. The nozzle 11 includes an internal annular chamber 15 (Fig. 2) to which air is supplied under pressure, for convergent issuance at diametrically spaced air jet orifices 16.

The nozzle 11 also has an axial valve chamber 17 in communication with a supply of paint, rubber latex or other liquid compound to be sprayed, and this liquid is drawn by injector action, under the control of needle valve 14, through a central discharge orifice 18 in the nozzle. All of this structure is entirely conventional and well known.

The jet orifices 16 of nozzle or head 11 are shown in the drawings as being positioned for a vertically fanned outline of the spray; it will be appreciated that the disposition may be otherwise to provide a horizontally fanned spread, and that other types of nozzles can be employed for otherdesired spray outlines.

The reference numeral 20 generally designates the drying attachment of the invention. It includes a hollow air heater and jetting housing 21, preferably formed in the annular, doughnut-like outline of a torus, and is equipped with suitable mounting provisions to attach the unit 20 to the spray gun '10. Such provisions may include a pair of opposed, rearwardly extending arms 22, 23 fixed to the housing 12 at opposed inner top and bottom surfaces thereof, with suitable provisions at 24 to" removably attach the arms to the gun 10, rearwardly of its nozzle 11.

gun structure, and are schematically indicated as in the form of small set screws. It is within the contemplation of the invention to employ any appropriate type of mounting ring or the like in association with the arms 22, 23, suitably securing such ring removably to the gun.

The primary purpose of the mounting means, of whatever sort, is to dispose the heating, air pressure and jetting housing 21 in forwardly spaced relation to the nozzle 11, without likelihood of substantial heat transfer thereto such as would tend to cause internal coagulation as referred to above.

The housing 21 comprises an external annular metal shell or sheath 26 of torus shape, a similar internal shell 27 of smaller sectional diameter disposed concentrically of the shell 26, and an intervening layer of suitable insulating material 28 disposed between the two housing shells.

An internal annular electrical resistance heating unit or element 29, preferably of the Calrod type, is disposed concentrically within the inner housing shell 27, with a substantial annular space between the latter and the heater 29, thus providing an air plenum or chamber 30. A schematically illustrated air pressure line 31 leads through the housing to the air chamber 30 from a com- These provisions are preferably of a type to require little modification of the existing spray.

pressor, which may be the compressor supplying the gun 10, or other source of air pressure. Similarly, electrical leads 32 are electrically connected to the heating unit 29 and brought out through the housing 21 to a suitable voltage supply. Such arrangements will be well known to those skilled in the art, hence have not been further illustrated.

Circumferentially arranged air discharge or jet orifices 34 are formed through the wall of the housing 21 at the forwardly facing side thereof, through which air jets of substantial velocity, heated to 300900 F. by the electrical heater 29,. are discharged in a forwardly and radially inwardly convergent path. The arrangement of these orifices in relation to the paint spray orifices is best illustrated in Fig. 3 of the drawings. That is, with the air jet orifices 16 of the gun horizon-tally opposed for a vertically fanned discharge of coating compound, the heating air jet orifices 34 are preferably arranged in two arcuate series of. equally spaced orifices, one on either side of the housing 21 at which the spray jets 16 are disposed. Thus arranged, the heated air jets will intersect convergently with an atomized spray of coating in a zone substantially forwardly of the nozzle 11, thus to heat the spray prior to its impinging a surface to be coated, while maintaining the desired outline of the spray. The heating jets have no disruptive effect on the desired spray contour.

The attachment is simple and inexpensive, is readily applied to existing spray equipment, can be detached when not in use, thereby minimizing the amount of cleaning of the attachment itself. which is required. More important, the fact that the nozzle 11 is protected against heating signifies that it need not be subjected to repeated, relatively time consuming operations of dismantling it from time to time to rid it of internal coagulated or dried coating compound.

The drawings and the foregoing specification constitute a description of the improved drying attachment for spray gun in such full, clear, concise and exact terms as to enable any person skilled inthe art to practice the invention, the scope of which is indicated. by the appended claims.

What I claim as my invention is:

l. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun out of direct heat transfer relation thereto, heating means on. said. housing to heat the interior thereof, and means to supply air under pressure to said interior to be. heated by said heating means, said housing being provided with. air jet orifice means disposed to discharge the heated. air convergently into a spray discharged by the nozzle, said attaching means being devised in relation to said orifice means to mount the housing on the gun for such convergent discharge.

2'. A drying device for association with the nozzle of a spray gun or the like, comprising an annular hollow housing having means to attach the same to said gun with. said housing disposed coaxially of said nozzle and out of direct heat. transfer relation thereto, an annular heating element within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating element, said housing being provided with air jet orifice means disposed todischarge the heatedair into a spray discharged by the nozzle.

3. A drying device for association with the nozzle of a spray gun or the like, comprising an annular hollow housing having means to attach the same to said gun with said housing disposed coaxially and forwardly of said nozzle and out of direct heat transfer relation thereto, an annular. heating element within said housing to heat the interior thereof, and'm'eans to supply air under pressure to said interior to be heated by said heating element, said housing being provided with air jet orifice means disposed to discharge the heated air into a spray discharged by the nozzle.

4. A drjn'ng device for association with the nozzle of a spray gun or the like, comprising an annular hollow housing having means to attach the same to said gun with said housing disposed coaxially of said nozzle and out of direct heat transfer relation thereto, an annular heating element within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating element, said housing being provided with air jet orifice means disposed to discharge the heated air forwardly .of said housing and in convergent relation to a spray discharged by the nozzle.

5. A drying device for association with the nozzle of a spray gun or the like, comprising an annular hollow housing having means to attach the same to said gun with said housing disposed coaxially and forwardly of said nozzle and out of direct heat transfer relation thereto, an annular heating element within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating element, said housing being provided with air jet orifice means disposed to discharge the heated air forwardly of said housing and in convergent relation to a spray discharged by the nozzle.

6. A drying device for association with the nozzle of a spray gun or the like, comprising an annular hollow housing having means to attach the same to said gun withsaid housing disposed coaxially and forwardly of said nozzle and out of direct heat transfer relation thereto, an annular heating element within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating element, said housing being provided with air jet orifice means disposed to discharge the heated air forwardly of said housing and in convergent relation to a spray discharged by the nozzle, said orifice means comprising a plurality of orifices in two arcuate series, one on either side of said spray and in a relation thereto to preserve its contour as issued from said nozzle.

7. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun out of direct heat transfer relation thereto, heating-means within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating means, said housing being provided with air jet orifice means disposed to discharge the heated air convergently into a spray discharged by the nozzle, said attaching means being devised in relation to said orifice means to mount the housing on the gun for suchconvergent discharge.

8. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun out of direct heat transfer relation thereto, heating means including an electrical heating element within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating means, said housing being provided with air jet orifice means disposed to discharge the heated air convergently into a spray discharged by the nozzle, said attaching means being devised in relation to said orifice means tomount the housing on the gun for such convergent discharge. g

9. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun out of direct heat transfer relation thereto, heating means including an electrical heating element within said housing in spaced relation to an internal wall surface of the latter to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating means, said housing being provided with air jet orifice means disposed to discharge the heated air convergently into a spray discharged by the nozzle, said attaching means being devised in relation. to said orifice means to mount the housing on the gun for such convergent discharge.

10. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun out of direct heat transfer relation thereto, heating means including an electrical heating element Within said housing in spaced relation to an internal wall surface of the latter to heat the interior thereof, a thermal insulating element surrounding said wall surface, and means to supply air under pressure to said interior to be heated by said heating means, said housing being provided with air jet orifice means disposed to discharge the heated air convergently into a spray discharged by the nozzle, said attaching means being devised in relation to said orifice means to mount the housing on the gun for such convergent discharge.

11. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun, heating means within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating means, said housing being provided with air jet orifice means disposed to discharge the heated air into a spray discharged by the nozzle.

12. A drying device for association with the nozzle of a spray gun or the like, comprising a hollow housing in the general outline of a torus having means to attach the same to said gun, heating means within said housing to heat the interior thereof, and means to supply air under pressure to said interior to be heated by said heating means, said housing being provided with air jet orifice means disposed to discharge the heated air convergently into a spray discharged by the nozzle, said attaching means being devised in relation to said orifice means to mount the housing on the gun for such convergent discharge.

References Cited in the file of this patent UNITED STATES PATENTS 1,523,855 Barrows Jan. 20, 1925 1,585,990 Houghton May 25, 1926 1,968,992 Conkling W Aug. 7, 1934 2,372,737 Phillips Apr. 3, 1945 2,521,769 Arcularius Sept. 12, 1950 2,556,609 Arkless June 12, 1951 2,644,717 Kopperschmidt July 7, 1953 2,868,166 Brechenmacher Jan. 13, 1959 FOREIGN PATENTS 671,178 France Aug. 31, 1929 

